UC-NRLF 


fiD    13D 


METHODS    OF 


ALYSIS  AND  CHEMICAL  CONTROL 


|R  USE  IN  THE  FACTORIES  OF  THE 
CUBAN-AMERICAN  SUGAR 
COMPANY 


CHAPARRA,  NUEVA   LUISA,  TINGUARO,: 

UNIDAD,  MERCEDITA, 

REFINERY    AT   CARDENAS 


-     *         ARRANGED   BY 

GUILFORD   L,  \SPENCER 


NEW   YORK 
HE   CUBAN-AMERICAN  SUGAR  COMPANY 

1907 


METHODS    OF 


ANALYSIS  AND  CHEMICAL  CONTROL 


FOR  USE  IN  THE  FACTORIES  OF  THE 

CUBAN- AMERICAN  SUGAR 

COMPANY 


CHAPARRA,  NUEVA   LUISA,  TINGUARO, 

UNIDAD,  MERCEDITA, 

REFINERY    AT    CARDENAS 


ARRANGED    BY 


GUILFORD   L.  [SPENCER 


NEW   YORK 
THE   CUBAN-AMERICAN   SUGAR   COMPANY 

1907 


Copyright,  1907, 

BV 

THE  CUB  AN- AMERICAN  SUGAR  COMPANY 


GIFT 


ROBERT    DRUMMOND  COMPANY,    PRINTERS,    NEW    YORK 


$7? 


METHODS    OF 

ANALYSIS  AND  CHEMICAL  CONTBOL 

FOR   USE   IN   THE   FACTORIES   OF 

THE  CUBAN-AMERICAN  SUGAR  COMPANY 


INTRODUCTION 

IN  order  that  the  results  obtained  in  several  factories  may  be  comparable,  it 
is  necessary  that  the  methods  of  sampling  and  analysis  in  all  be  conducted  by 
uniform  methods.  Different  methods,  notably  in  the  analysis  of  low  products, 
frequently  give  widely  different  results  with  the  same  material,  rendering  compari- 
sons unsatisfactory. 

It  is  the  purpose  to  supply  methods  that  are  applicable  in  all  the  Company's 
factories,  in  obtaining  the  data  required  for  the  report  sheets  and  permanent  records. 
Methods  for  the  routine  control  work  are  not  given,  as  it  is  only  essential  that  these 
supply  figures  for  use  in  a  single  factory,  and  not  for  comparisons  in  a  group  of 
factories.  Minor  details  of  processes  are  omitted. 

The  description  of  methods  is  preceded  by  definitions  of  terms  as  used  by  this 
Company  in  its  records  and  reports. 

DEFINITIONS  OF  TERMS 

Mill  Extraction. — This  expression  indicates  the  quantity  of  juice  extracted 
from  the  cane  by  the  mills,  and  is  expressed  in  percentage  terms  of  the  weight  of  the 
cane. 

Saturation  Water.  Saturation. — The  water  sprayed  upon  the  bagasse  before 
regrinding  is  termed  the  "  saturation, "  and  is  expressed  in  percentage  terms  of  the 
weight  of  the  cane. 

Dilution. — The  dilution  water  is  that  part  of  the  saturation  water  which  is 
expressed  with  the  juice,  and  mixing  with  it  reduces  its  density  below  that  of  normal 
juice.  Since  the  saturation  water  extracts  sucrose  and  other  solids  from  the  bagasse, 
only  a  part  of  that  in  the  juice  is  indicated  by  the  dilution.  The  percentage  of 
dilution  is  calculated  from  the  densities  of  the  normal  and  diluted  juices  and  is 
reduced  to  terms  of  the  weight  of  the  cane. 

Sucrose  Retained.  Retention. — This  expression  is  designed  to  indicate  the 
efficiency  of  the  manufacturing  processes;  it  shows  the  percentage  of  the  sucrose 
in  the  raw  juice,  expressed  by  the  mills,  that  is  obtained  in  the  commercial  sugar. 

Raw  Juice,  Normal. — The  true  normal  juice  is  the  juice  as  it  actually  exists  in 
the  cane.  The  juice  cannot  be  separated  from  the  cane  in  this  state.  By  long 
established  usage,  the  juice  obtained  by  milling,  without  the  use  of  saturation  water, 
is  considered  to  be  normal  juice,  and,  further,  when  saturation  is  practiced  the  un- 
diluted juice  from  the  first  crushing  is  assumed  to  be  of  very  nearly  the  density  of 
the  true  normal  juice.  It  is  customary  to  apply  a  factor,  deduced  from  experimental 
data,  to  reduce  the  density  of  the  juice  from  the  first  crushing  to  a  basis  of  the  juice 

3 


M802416 


that  would  be  obtained  from  all  the  mills  without  saturation.  The  density  esti- 
mated in  this  way  and  the  purity  coefficient  of  the  diluted  or  mixed  juice  are  used 
in  calculating  the  analysis  of  the  so-called  normal  juice.  The  expression  "normal 
juice"  is  used  in  this  sense  in  the  Company's  records,  and  this  use,  though  not  strictly 
correct,  is  sanctioned  by  long  and  very  general  usage  in  the  cane-sugar  industry. 

Raw  Juice,  Diluted. — This  expression  indicates  the  mixed  juices  from  all  the 
mills,  when  saturation  water  is  used. 

Syrup. — The  syrup  is  the  purified  juice  after  concentration;  it  is  termed  meladura 
in  the  Spanish-American  factories. 

First  Massecuite. — The  first  massecuite  is  that  produced  largely  or  wholly  from 
syrup  or  meladura. 

Mixed  Massecuite. — This  massecuite  is  composed  of  a  small  quantity  of  syrup 
used  as  a  nucleus  or  footing  for  the  strike  and  molasses  from  a  first  massecuite 
This  is  also  termed  "  second  massecuite." 

Third  Massecuite. — This  is  a  massecuite  boiled  as  described  above  for  a  mixed 
strike,  except  using  molasses  from  the  latter,  instead  of  from  first  massecuite.  When 
the  expression  ''mixed  massecuite"  is  used,  this  massecuite  is  termed  "second"  instead 
of  "third." 

Molasses. — The  molasses  products  are  numbered  to  correspond  with  the  masse- 
cuite from  which  produced.  In  certain  of  the  Company's  factories,  the  second  is 
the  final  or  commercial  molasses,  and  in  others  this  product  is  the  third  molasses. 
The  molasses  product  of  lowest  purity  should  be  reported  as  final  molasses. 

Circulation  Water. — The  water  used  in  condensing  the  vapors  from  the  vacuum 
evaporating  apparatus. 

Residual  Juice  in  the  Bagasse. — The  juice  left  in  the  bagasse  at  the  completion 
of  the  milling  process  is  termed  "  residual  juice." 

Fiber  (Marc)  in  the  Cane. — The  woody  residue  left  after  exhausting  the  cane 
with  water  in  the  laboratory  tests  is  termed  "fiber,"  or  "marc." 

STANDARDIZATION  OF  SPECIAL  APPARATUS 

Hydrometers. — As  the  Brix  hydrometer  indicates  percentages  of  sucrose  by 
weight  in  solutions  of  the  pure  carbohydrate,  it  may  readily  be  checked  by  the  polar- 
iscope.  Three  sugar  solutions  should  be  prepared  with  distilled  water  and  refined 
sugar  and  of  densities  within  the  range  of  the  hydrometer  scale.  The  percentages 
of  sucrose  should  be  determined  in  these  solutions,  using  standardized  instruments. 
The  hydrometer,  when  floated  in  these  solutions  at  a  temperature  of  17.5°  C.,  should, 
if  correct,  indicate  percentages  agreeing  with  those  ascertained  by  the  polariscopic 
method.  If  the  observations  are  made  at  other  than  17.5°  C.,  the  readings  must 
be  corrected  by  the  tables  in  current  use.  The  errors  of  the  hydrometer  at  the  top, 
middle  and  bottom  parts  of  its  scale  should  be  noted.  This  standardized  hydrometer 
may  be  used  in  checking  other  hydrometers.  The  hydrometers  should  be  num- 
bered or  bear  other  marks  for  identification.  Diamond-ink  is  convenient  for  marking 
these  instruments  and  other  glassware. 

The  hydrometer  may  also  be  checked  by  means  of  a  pyknometer.  This  method 
is  not  usually  a  convenient  one  in  cane-sugar  factories. 

Volumetric  Glassware. — The  glassware  should  be  thoroughly  cleansed  with  a 
warm  solution  of  chromic  acid  in  sulphuric  acid,  followed  by  rinsing  with  distilled 
water.  Select  flasks  having  necks  of  small  internal  diameter,  preferably  about  12  mm. 
The  flasks  should  be  thoroughly  dry  and  should  remain  inside  the  balance  case  a  few 
minutes  after  wiping  them,  before  weighing.  Recently  boiled  distilled  water,  cooled 


to  the  room  temperature,  is  most  convenient  for  checking  purposes  in  the  factory 
laboratory. 

A  small  error  is  necessarily  permissible  in  graduated  ware.  The  error  should 
be  less  than  0.05  cc.  for  a  100-cc.  flask  or  0.03  for  a  100-cc.  pipette,  and  less  for 
smaller  apparatus. 

Standardizing  a  Flask. — Counterpoise  the  dry  flask  on  the  balance  with  a  similar 
flask  and  small  weights.  Remove  and  fill  the  flask  to  the  mark  with  the  distilled 
water,  using  a  pipette  in  filling,  and  avoid  wetting  the  neck  of  the  flask  or  carrying 
bubbles  of  air  into  it.  This  manipulation  requires  great  care.  For  small  flasks 
the  analytical  balance  and  accurate  weights  must  be  used.  The  following  table 
shows  the  number  of  grams  of  water  the  100-cc.  flask  should  hold  at  various  tem- 
peratures, as  weighed  with  brass  weights  in  the  air: 

WEIGHT    OF    WATER    AT    VARIOUS    TEMPERATURES 


Wt,  ICO  cc. 

Wt,  100  cc. 

rpo  r\ 

Wt.  100  cc. 

Wt,  100  cc. 

(Mohr  cc.) 

(True  cc.) 

(Mohr  cc.) 

(True  cc.) 

Grams. 

Grams. 

Grams. 

Grams. 

17.5 

100 

99.772 

24 

99.88 

99.655 

18 

99.99 

99.765 

25 

QQ    ftfi       _ 

99.635 

19 

99.98 

99.75 

26 

99.84 

99.61 

20 

99.90 

99.73 

27 

99.82 

99.59 

21 

99.94 

99.715 

28 

99.79 

99  .  5fi 

22 

99.92 

99.695 

29 

99.76 

99.535 

23 

99.90 

99.675 

30 

99.74 

99.51 

In  the  above  table  allowance  is  made  for  the  expansion  of  the  glass. 

If,  for  example,  the  flask  holds  99.9  grams  of  water  at  23°  C.,  its  capacity  is 
100  cc.  (Mohr)  and  it  is  correct  for  use  with  a  normal  weight  of  26.048  grams. 

A  standardized  pipette  is  convenient  for  use  in  checking  flasks. 

Many  polariscopes  are  now  graduated  at  a  standard  temperature  of  20°  C.,  and 
according  to  the  specifications  of  the  International  Committee  should  be  used  with 
a  normal  weight  of  26  grams  and  a  flask  graduated  to  hold  100  true  or  metrical 
cubic  centimeters.  The  column  in  the  table  giving  the  weight  of  100  true  cc.  is 
for  use  in  graduating  apparatus  to  true  cubic  centimeters. 

Since  the  Company's  factories  are  equipped  with  apparatus  graduated  to  Mohr's 
cc.,  and  with  books  of  tables  for  use  with  this  system,  the  true  cubic  centimeter 
graduated  ware  will  be  little  used. 

Standardizing  Burettes  and  Pipettes. — Burettes  and  pipettes  are  standardized  by 
weighing  the  quantity  of  water  they  deliver.  A  flask  is  used  in  making  the  weigh- 
ings. The  table  of  weights  of  water  is  also  used  in  checking  burettes,  etc.  A 
definite  time  should  be  allowed  for  the  drainage  of  the  burette  and  pipette  in  check- 
ing, and  in  practice  they  should  be  used  under  the  conditions  of  standardizing. 

The  sucrose  pipette  is  most  conveniently  checked  by  comparing  the  polariza- 
tion of  a  solution  measured  with  it,  with  a  test  of  the  same  solution  using  the  balance. 
The  pipette  is  made  to  deliver  2  normal  weights  in  order  to  divide  the  error  of  measure- 
ment by  2. 

Polariscope  and  Accessories.— The  polariscope  should  be  so  arranged  that  the 
light  from  windows  or  cross-lights  do  not  interfere  with  the  observations.  Under 
no  circumstances  should  the  instrument  be  located  in  a  small  compartment  with 
the  lamp.  In  the  sugar-house  laboratory,  the  polariscope  should  preferably  be  placed 


6 

in  a  box,  open  at  one  end  and  from  which  the  body  of  the  observer  himself  cuts  off 
a  part  of  the  light  of  the  room.  The  lamp  should  be  placed  in  a  well-ventilated 
compartment  outside  the  box,  the  light  being  passed  through  a  small  opening  to  the 
polariscope.  A  piece  of  plate  glass  should  cover  the  opening  to  prevent  currents 
of  air  from  causing  the  flame  of  the  lamp  to  flicker. 

The  polariscope  should  be  clamped  securely  to  the  floor  of  the  box.  The  flame 
of  the  lamp  should  always  occupy  the  same  position  or  should  not  be  moved  with- 
out rechecking  the  zero  of  the  polariscope.  With  most  polariscopes  slight  changes 
in  the  relative  positions  of  the  instrument  and  the  source  of  light,  or  the  intensity 
of  the  light,  displace  the  zero,  rendering  resetting  of  the  polariscope  scale  necessary. 

The  dark  products  obtained  in  the  present  methods  of  manufacture  necessitate 
the  use  of  an  acetylene  or  electric  lamp  in  the  polariscopic  work. 

Having  properly  arranged  the  polariscope  and  lamp  the  zero  point  must  be 
checked  by  a  blank  observation,  preferably  with  a  tube  filled  with  water  in  the 
trough.  The  vernier  must  be  moved  with  the  adjusting  key  until  the  instrument 
indicates  zero  under  the  above  conditions.  After  setting  the  vernier,  a  standard 
quartz  plate,  reading  approximately  96°,  should  be  substituted  for  the  tube  of  water 
and  an  observation  made.  The  deviation  from  the  marked  value  of  the  plate  should 
be  noted  and  allowed  for  in  all  observations. 

The  graduations  of  these  instruments  have  attained  such  perfection  that  errors 
are  rarely  found  in  the  scales.  The  eyes  of  different  observers  may  differ,  hence 
each  should  make  check  observations  on  the  quartz  plate  and  apply  the  proper 
corrections  in  his  analytical  work. 

The  eye  'should  be  allowed  time  to  adjust,  itself  to  the  instrument  and  recover 
from  fatigue  between  tests.  An  observation  should  not  be  made  immediately  after 
looking  at  a  bright  light. 

The  observation  tubes  should  be  compared  with  one  another,  using  the  same 
sugar  solution.  The  cover  glasses  should  be  examined  frequently,  and  if  their  surfaces 
are  scratched  or  not  parallel,  or  if  they  show  optical  activity,  they  must  be  rejected. 
Care  must  be  observed  that  the  caps  do  not  press  unduly  on  the  cover  glass. 

Each  laboratory  should  be  provided  with  a  standard  quartz  plate,  normal  weights, 
and  thermometer.  These  should  be  used  only  in  checking  the  apparatus  and  not 
in  the  analytical  work. 

WEIGHTS  AND  MEASUREMENTS 

Weights  and  Measurements. — The  chemist  must  assure  himself  that  all  weights 
and  measures  are  of  one  system,  e.g.,  all  Spanish  or  all  English;  if  not.  they  should 
be  reduced  to  one  system  before  proceeding  with  the  control  calculations.  The 
accuracy  of  all  scales  and  the  calibration  of  all  measuribg  tanks  should  be  verified 
by  the  chemist. 

Measurement  and  Weight  of  the  Juice. — Where  the  juice  cannot  be  weighed, 
its  weight  must  be  deduced  from  its  volume  and  density.  Where  practicable,  the 
volume  of  the  measuring  tank  should  be  determined  by  running  water  into  it  from 
an  accurately  calibrated  tank.  This  is  not  usually  practicable  in  large  factories, 
hence  the  volume  must  usually  be  calculated  from  the  averages  of  several  measure- 
ments. An  overflow  pipe  or  other  device  should  be  provided  to  indicate  when  the 
tank  is  full. 

The  juice  entrains  a  large  quantity  of  air  which  increases  its  volume.  This 
introduces  an  error  for  which  a  correction  based  upon  experimental  data  must  be 
made.  The  volume  of  air  entrained  varies  with  the  temperature  of  the  juice  and 
also  with  other  conditions. 


In  deducing  the  weight  of  the  juice  from  its  volume,  the  latter  should  be  cor- 
rected for  temperatures  other  than  17.5°  C.  Gerlach's  table  for  the  expansion  of 
sugar  solutions  may  be  used  for  this  purpose.  The  weight  of  a  cubic  foot  of  \vater 
at  17.5°  C.  is  to  be  taken  at  62.34G  Ibs.,  and  that  of  the  II.  S.  gallon,  8.3317  Ibs. 

When  the  measurement  of  the  juice  is  effected  at  moderate  temperatures,  the 
measured  volume,  without  temperature  correction,  may  be  used,  the  specific  gravity 
of  the  juice  at  the  temperature  of  the  measurement  being  employed  in  calculating 
the  weight  of  the  unit  volume. 

Measurement  of  the  Saturation  Water. — Two  tanks  should  be  used  in  measur- 
ing the  water,  one  to  be  filling  while  the  other  is  emptying.  The  weight  of  the  water 
is  calculated  from  its  volume. 

AVhere,  through  accident  or  other  cause,  the  volume  of  the  water  cannot  be 
determined,  it  must  be  estimated  from  the  dilution  of  the  juice  by  dividing  the 
percentage  of  dilution  by  0.7.  This  is  necessary  in  order  to  estimate  the  weight 
of  the  bagasse. 

Filter  Press-cake. — The  cake  should  be  weighed,  but  as  this  is  not  usually 
feasible,  its  weight  may  be  estimated  from  that  of  several  average  cakes.  The 
number  of  presses  emptied  should  be  recorded  for  use  in  calculating  the  total  amount 
of  press-cake. 

Massecuites  and  Molasses. — Massecuites  should  be  measured  immediately  they 
are  discharged  from  the  pans.  This  is  necessary  on  account  of  the  expansion  this 
material  undergoes  in  the  crystallizers.  These  measurements  are  not  usually  neces- 
sary except  preparatory  to  a  "Run  Report." 

It  is  usually  difficult  to  accurately  measure  final  molasses.  This  is  due  to  the 
air  it  entrains.  Where  the  molasses  is  slightly  reduced  with  water  and  steam  to 
bring  it  to  a  uniform  density,  it  may  be  measured  before  pumping  it  from  the  factory, 
or  afterwards  in  the  large  storage  tanks.  Measurements  of  very  heavy  molasses  in 
tank-cars  are  unsatisfactory  except  where  the  measurement  is  made  several  hours 
after  filling  the  tanks. 

For  control  purposes,  especially  for  the  final  report  of  the  Crop,  the  actual  weight 
of  the  molasses  should  be  reported,  though,  in  order  not  to  delay  the  reports,  a  small 
quantity  may  be  estimated  at  the  close  of  each  Run.  The  tank-cars  should  be 
tared  each  trip  because  often  the  buyer  does  not  completely  empty  them. 

Where  measurements  are  necessarily  made  of  heavy  molasses  in  large  tanks  or 
tank-cars,  corrections,  determined  by  experiment,  will  be  required  for  the  entrained 
air.  Heavy  molasses  will  often  entrain  sufficient  air  to  reduce  its  weight  per  galkii 
nearly  one  pound. 

SAMPLING  AND  AVERAGING 

Preliminary  Remarks. — Sampling  should  be  so  conducted  that  the  quantity 
of  material  drawn  from  each  tank,  etc.,  bears  the  same  relation  to  the  total  quantity. 
For  example,  having  two  equal  tanks  of  syrup,  one  full,  the  other  half-full,  half  as 
much  should  be  drawn  from  the  one  as  from  the  other,  that  the  subsamples  when 
mixed  may  represent  all  the  syrup.  This  principle  should  be  applied  in  all  sampling. 

In  averaging  analytical  data,  each  analysis  should  be  weighted  by  the  quantity 
of  material  it  represents. 

Juice. — The  ideal  sample  would  be  one  drawn  continuously  in  proportion  to  the 
quantity  of  juice  flowing  from  the  mills.  Where  the  arrangement  of  the  mills  permits, 
a  continuous  or  "drip"  sample  should  be  drawn  from  the  canal  leading  from  the 
crusher  and  first  mill.  This  sample  should  be  drawn  throughout  the  sugar-house 
day,  preserving  it  with  formaldehyde  or  mercuric  chloride,  1  part  of  the  salt  to 


8 

5000  of  juice.  It  is  for  use  in  estimating  the  density  of  the  normal  juice.  Where 
a  continuous  sample  cannot  be  obtained,  small,  equal-measured  subsamples  should 
be  drawn  at  least  hourly,  and  united  to  form  a  sample  representing  the  day's  work. 
When  not  macerating,  this  sample  may  be  dispensed  with. 

The  mixed  or  diluted  juice  should  also  be  sampled  as  it  flows  into  the  measuring 
tanks.  A  definite  number  of  small  cupful s  should  be  drawn  per  tank,  and  this 
number  should  not  be  changed  during  a  sampling  period,  which  is  preferably  the 
sugar-house  day. 

Duplicate  samples  of  the  mixed  or  diluted  juice  should  be  drawn,  one  for  the 
sucrose  and  the  other  for  density  tests.  One  sample  may  be  preserved  with  Home's 
anhydrous  subacetate  of  lead  for  analysis  by  his  method.  The  least  quantity  of 
the  lead  salt  that  will  insure  preservation  of  the  juice  should  be  used.  LUsually  about 
12  grams  of  the  dry  salt  per  litre  of  juice  are  required^  The  duplicate  sample,  for 
the  density  test,  may  be  preserved  with  either  formaldehyde  or  mercuric  chloride. 
It  is  optional  with  the  chemist  to  draw  a  single  sample  for  both  sucrose  and  density 
tests,  using  1  part  of  mercuric  chloride  to  5000  parts  of  juice  as  a  preservative. 

The  preservation  of  samples  must  be  carefully  supervised.  Only  sterilized,  wide- 
mouthed  jars  with  stoppers  should  be  used  for  storage  purposes.  Funnels  should 
not  be  used  to  direct  the  sample  into  the  jar.  The  small  sampling  cups  should  be 
thoroughly  rinsed  with  the  juice  before  drawing  the  subsamples. 

Bagasse. — Subsamples  should  include  all  of  the  bagasse  on  one  or  more  slats 
of  the  conductor.  Composite  samples,  well  protected  from  the  air,  may  be  preserved 
during  a  few  hours  with  formaldehyde,  but  it  is  advisable  not  to  extend  the  storage 
period  to  more  than  six  hours.  Clean  galvanized-iron  cans  are  to  be  used  for  storing 
the  samples. 

Filter  Press-cake. — Subsamples  should  be  cut  from  a  definite  number  of  cakes 
in  each  press  by  means  of  a  brass  cork-borer.  The  small  samples  may  be  collected 
during  six  hours  without  recourse  to  a  preservative.  Care  should  be  observed  that 
the  samples  be  drawn  from  representative  parts  of  the  press-cakes. 

Syrup  and  Molasses. — Syrup  and  thin  molasses,  to  be  reboiled,  may  be  sampled 
in  the  storage  tanks.  Heavy  commercial  molasses  should  be  sampled  at  frequent 
regular  intervals  at  the  pump-tank,  forming  a  composite  sample,  representing  the 
day's  work.  W7hen  shipping  molasses,  samples  should  be  drawn  from  each  tank-car, 
to  form  a  composite  sample  representing  the  day's  shipment.  Composite  samples 
should  be  prepared  from  the  daily  samples,  for  analysis  to  supply  the  data  required 
in  the  Run  Reports. 

Sugars. — One  hundred  per  cent  of  the  packages  should  be  sampled.  As  the 
truck  passes  onto  the  scale,  a  spoonful  of  sugar  should  be  withdrawn  and  thrown 
into  a  tin-lined  box,  provided  with  a  small  funnel  or  hopper-like  opening.  Sugar 
already  packed  should  be  sampled  with  a  trier. 

Miscellaneous. — The  principles  described  apply  in  all  sampling  and  averaging 
in  the  control  of  the  factory.  Where  practicable,  composite  samples  of  juices,  masse- 
cuites,  molasses,  etc.,  should  be  prepared  to  supply  data  for  the  permanent  records 
and  daily  reports,  so  that  but  a  single  analysis  need  be  made  daily  of  each  class  of 
material  for  these  purposes. 

METHODS  OF  ANALYSIS 

Sugar  Cane. — Owing  to  the  nature  of  the  cane  it  cannot  be  accurately  sampled 
without  undue  expense  for  appliances  and  labor.  For  this  reason,  and  not  on  account 
of  analytical  difficulties,  its  analysis  should  be  ascertained  indirectly  as  follows: 


The  per  cent  sucrose  in  the  cane  =  (weight  of  sucrose  in  the  raw  juice  -}-  weight  of 
sucrose  in  the  bagasse) -f-  weight  of  the  cane X 100. 

The  per  cent  fiber,  or  marc,  in  the  cane  =  fiber  %  bagasse X bagasse  %  cane^- 100. 

The  bagasse  per  cent  cane  is  calculated  as  directed  under  Miscellaneous  Calcu- 
lations. 

Juice. — Brix. — Strain  the  sample,  through  fine  centrifugal  lining,  into  a  tall 
cylinder,  letting  the  latter  overflow.  After  an  interval  of  about  10  minutes  insert 
the  hydrometer,  at  the  same  time  blowing  the  foam  from  the  surface  of  the  liquid. 
After  the  instrument  reaches  the  temperature  of  the  juice,  note  the  graduation  on 
its  stem  on  a  level  with  the  surface  of  the  juice  in  the  cylinder,  and  enter  this  number 
as  tho  observed  degree  Brix.  The  temperature  of  the  juice  should  also  be  noted 
and  a  correction  be  made,  if  it  varies  from  17.5°  C.,  by  Gerlach's  table. 

Sucrose. — Thoroughly  mix  the  sample  of  juice  that  has  been  preserved  with  anhy- 
drous subacetate  of  lead  and  filter  a  portion  of  it.  Polarize  the  filtrate  and  calculate 
the  percentage  of  sucrose,  using  Schmitz's  table.  If  the  Schmitz  table  providing  for 
10  per  cent  dilution  is  employed,  divide  the  polariscope  reading  by  1.1.  A  copy 
of  Schmitz's  table,  for  use  without  dilution,  will  be  supplied  to  each  of  the  Company's 
laboratories,  thus  obviating  the  division  by  1.1. 

In  case  mercuric  chloride  has  been  used  as  a  preservative,  the  analysis  may  be 
made  by  Home's  dry  subacetate-of-lead  method,  or  using  subacetate  in  solution. 

The  estimation  of  the  sucrose  by  double  polarization  is  described  under  Clerget 
Tests. 

Glucose. — (1)  Using  the  composite  sample  preserved  with  anhydrous  subacetate 
of  lead:  Mix  the  sample  thoroughly  and  without  previous  filtration  add  powdered 
dry  hydrosulphite  of  sodium  (B.A.S.tt)  in  slight  excess,  i.e.,  to  faint  acidity,  and 
filter  immediately;  to  the  filtrate  add  sufficient  anhydrous  carbonate  of  sodium  to 
produce  a  clear  liquid  on  refiltration.  Use  this  last  filtrate  in  determining  the  glucose 
by  Violette's  or  other  standard  method. 

(2)  Using  a  composite  sample  preserved  with  mercuric  chloride:  To  a  measured 
portion  of  the  sample  add  a  solution  of  normal  acetate  of  lead  for  clarification, 
dilute  to  a  definite  volume,  and  filter.  Add  anhydrous  carbonate  of  sodium  to  the 
filtrate  in  slight  excess  to  precipitate  the  lead,  and  again  filter.  Determine  the 
glucose  in  the  filtrate  by  a  standard  method. 

Solids  by  Drying. — See  Methods  of  Drying. 

Ask.— See  Ash  Determinations. 

Bagasse. — Sucrose. — Digest  50  grams  of  small  fragments  of  bagasse  with  450  cc. 
of  water  and  5  cc.  of  a  5%  solution  of  sodium  carbonate,  during  one  hour,  at  boiling 
temperature.  A  large  flask,  tared  and  fitted  with  a  reflux  condenser,  should  be  used 
in  making  this  test.  A  long  small-bore  glass  tube  will  answer  as  a  condenser. 

After  the  digestion,  cool  and  weigh  the  flask  and  contents.  Drain  off  a  portion 
of  the  solution,  clarify  it  with  subacetate  of  lead,  and  polarize,  using  a  400-mm.  obser- 
vation tube.  The  method  of  calculating  the  percentage  of  sucrose  in  the  bagasse 
is  illustrated  by  the  following  example,  in  which  the  fiber  in  the  bagasse  is  assumed 
to  be  45%: 

Weight  of  flask  +  bagasse  and  water 998.5  gr. 

"       "     "  .   500      " 


and  water 498 . 5 

' '  fiber  in  bagasse  =  50  X0.45  — 22 . 5 


thin  juice 476 .0 


10 

Polarization  of  the  thin  juice  (Home's  method)  in  a  400-mm.  tube  =  4.4.  Dividing 
this  number  by  2  (on  account  of  double-length  tube)  and  referring  to  Schmitz's  table, 
.the  per  cent  sucrose  in  the  thin  juice  is  0.57,  and  476 X. 0057  =2.71  grams  sucrose 
in  50  grams  of  bagasse.  .'.  the  per  cent  sucrose  in  thej^agasse  is  5.42. 

Moisture.—  Small  shallow  trays  made  of  80-mesh  brass-wire  gauze  are  convenient 
for  use  in  the  moisture  determinations.  These  should  hold  80-100  grams  of  bagasse 
and  should  be  narrow  enough  for  weighing  on  the  sugar  balance.  The  bagasse  should 
be  dried  at  the  temperature  of  boiling  water  in  a  steam-  or  water-oven,  or  for  prompt 
results  at  105°  C.,  until  there  is  no  further  loss  of  weight,  or  until  there  is  a  gain  after 
a  short  interval,  the  lowest  weight  being  accepted.  The  dry  bagasse  absorbs  moisture 
with  extreme  rapidity,  therefore  the  weighings  must  be  quickly  made. 

The  bagasse  should  be  prepared  for  analysis  by  chopping  it.  It  is  not  advisable 
to  attempt  to  reduce  it  to  a  very  fine  state  of  division  on  account  of  the  long 
exposure  to  the  air  that  would  be  necessary. 

Residual  Juice. — A  sample  of  the  juice  flowing  from  the  bagasse  roll  of  the  last 
mill  corresponds  so  nearly  with  the  residual  juice  that  it  may  be  accepted  as  such. 
A  sample  of  this  juice  is  to  be  drawn  at  the  time  of  sampling  the  bagasse,  and  its 
coefficient  of  purity  determined. 

Riber,  or  Marc. — The  fiber  may  be  estimated  by  direct  test,  also  indirectly.  In 
the  direct  estimation,  20  grams  of  bagasse  are  placed  in  a  tared  cylinder  of  80-  or 
100-mesh  brass-wire  gauze.  The  cylinder  is  placed  in  warm  distilled  water  below 
75°  G.,  and  after  10  minutes  the  water  is  drained  from  the  bagasse.  A  gauze  disc 
placed  on  the  bagasse  keeps  it  from  rising  above  the  water  in  the  cylinder.  The 
soaking  in  warm  water  is  repeated  once  and  then  the  bagassfis  extracted  five  times 
in  boiling  water.  After  thorough  drainage  the  cylinder  of  bagasse  is  placed  in  the 
oven  and  dried.  These  manipulations  require  very  little  attention.  The  dry  fiber 
must  be  protected  from  absorbing  moisture  from  the  air  while  cooling. 

In  the  indirect  estimation  the  calculations  are  made  as  follows:  Divide- the  per- 
centage of  sucrose  in  the  bagasse  by  the  coefficient  of  purity  of  the  residual  juice, 
and  multiply  the  quotient  by  100;  subtract  this  last  product  (the  juice  solids  of  the 
bagasse)  from  the  percentage  of  dry  matter  in  the  bagasse,  and  the  remainder  is  the 
percentage  of  fiber  (marc). 

The  direct  method  is  to  be  preferred  since  the  one  sample  of  bagasse  is  used  for  all 
the  tests. 

Filter  Press-cake. — Sucrose. — Reduce  the  sample  to  a  fine  state  of  division. 
This  is  readily  accomplished,  provided  the  presswork  is  satisfactory,  by  cutting  the- 
sample  in  a  large  mortar  with  scissors.  The  scissors  should  be  held  with  a  handle 
in  each  hand. 

Rub  50  grams  of  the  press-cake  in  a  mortar  to  a  cream  with  water  and  wash  it  into 
a  200-cc.  flask.  Add  sufficient  subacetate  of  lead  to  clarify  the  solution  and  dilute 
it  to  the  mark  with  water.  Shake  the  flask  and  contents  very  thoroughly  and  filter. 
Polarize  the  filtrate,  using  a  200-mm.  tube.  The  polariscope  reading  is  the  percen- 
tage of  sucrose  in  the  sample. 

Moisture. — Dry  5  grams  as  directed  under  Methods  of  Drying. 

Sugars. — Sucrose. — Wash  26.048  grams  of  the  sugar  from  the  weighing  capsule 
into  a  narrow-necked  flask  with  water.  Dissolve  the  crystals,  then  add  sufficient 
subacetate  of  lead  solution  to  effect  the  clarification;  mix  the  contents  of  the  flask 
by  a  rotary  motion,  add  about  5  cc.  of  alumina  cream,  and  dilute  the  mixture  to 
100  cc.  Mix  thoroughly  and  pour  the  contents  of  the  flask  onto  a  filter,  covering 
the  funnel  to  prevent  evaporation.  Reject  the  first  portion  of  the  filtrate,  which  is 


11 

diluted  with  the  moisture  of  the  filter-paper.     Polarize  the  filtrate,  using  a  200-mm. 
tube. 

Only  the  most  accurate  flasks  in  the  laboratory  should  be  used  in  the  sugar  tests. 
The  polariscope  should  be  checked  with  the  standard  quartz  plate  before  polarizing 
the  sugar. 

For  the  double  polarizations  see  Clerget  Tests. 

Glucose. — The  solutions  of  sugar  for  glucose  tests  should  be  clarified  with  normal 
acetate  of  lead.  The  lead  should  be  precipitated  from  the  filtrate  with  anhydrous 
sodium  carbonate  in  slight  excess  or  with  a  solution  of  potassium  oxalate,  making 
due  allowance  in  the  latter  case  for  the  dilution.  The  strength  of  the  sugar  solution 
should  be  5  grams  or  a  multiple  of  5  grams  per  100  cc.,  or  5  grams  to  a  multiple  of 
100  cc.  The  glucose  in  the  filtrate  is  determined  by  Violette's  method  or  other 
modification  of  the  Fehling  method.  If  Violette's  method  is  used  the  strength  of  the 
solution  should  be  such  as  to  give  a  burette  reading  of  about  20.  With  the  strength  of 
solution  indicated  above,  a  table  of  reciprocals  facilitates  the  calculations. 
Ash. — See  Ash  Determinations. 
Moisture. — See  Methods  of  Drying. 

Massecuites  and  Molasses. — Brix. — Dissolve  a  definite  weight  of  the  material 
in  an  equal  weight  of  water  and  determine  the  corrected  degree  Brix  of  the  solution; 
multiply  this  number  by  2  to  obtain  the  degree  Brix  of  the  material.  This  method 
should  be  used  except  in  the  control  of  the  pan-boiling.  • 

Sucrose,  Direct  Polarization. — Standardized  flasks  should  be  used  in  this  test. 
Wash  the  normal  weight  of  the  solution  used  in  the  Brix  determination  (=0.o  normal 
weight  of  the  original  material)  into  a  100-cc.  flask;  add  sufficient  subacetate  solution 
to  secure  a  good  clarification,  complete  the  volume  to  100  cc.  with  water,  mix  thor- 
oughly, and  filter.  Measure  50  cc.  of  the  filtrate  in  a  50-55-cc.  flask  and  add  suffi- 
cient diluted  acetic  acid  to  acidulate  the  solution,  then  fill  the  flask  to  the  55-cc. 
mark  with  water.  This  solution  is  usually  light  enough  colored  to  polarize  in  a 
200-mm.  tube.  If  the  color  is  too  dark  filter  the  solution  through  powdered  bone- 
black,  rejecting  the  first  half  of  the  filtrate.  If  preferred,  about  0.5  gram  of  powdered 
dry  bone-black  may  be  shaken  with  the  solution  in  the  flask  to  decolorize  it.  Should 
the  solution  still  be  too  dark  to  polarize  in  a  200-mm.  tube,  use  the  half-length  tube. 
The  polariscope  reading  must  be  increased  one-tenth  to  compensate  for  the  diluticn, 
and  the  polarization  multiplied  by  2  to  reduce  it  to  terms  of  the  original  material. 

Solutions  of  first  massecuites  may  usually  be  clarified  with  normal  acetate  of  lead 
solution,  thus  obviating  the  acidulation  with  acetic  acid  before  polarizing. 
For  the  method  by  double  polarization  see  Clerget  Tests. 

Glucose. — Prepare  the  solution  for  testing  and  conduct  the  analysis  as  described 
for  sugars.  Owing  to  the  high  percentage  of  glucose  in  molasses,  great  care  is  neces- 
sary in  making  the  test. 

Ash. — See  Ash  Determinations. 
Moisture. —  See  Methods  of  Drying. 

Condensation  and  Waste  Waters. — Frequent  sucrose  tests  should  be  made  in 
water  from  the  condensers  and  tail-pipes.  In  very  exceptional  cases  the  water  may 
contain  sufficient  sucrose  for  a  polariscopic  test.  The  sucrose  content  is  usually 
very  small  and  may  be  estimated  with  sufficient  accuracy  by  the  a-naphthol  test. 
This  test  is  made  as  follows:  Add  5  drops  of  a  20%  solution  of  a-naphthol  in  alcohol 
to  2  cc.  of  the  water  in  a  test-tube,  then  add  10  cc.  of  concentrated  sulphuric  acid,. 
using  a  pipette  to  conduct  the  acid  to  the  bottom  of  the  tube.  If  sucrose  is  present 
a  violet  zone  forms  between  the  two  liquids;  in  the  presence  of  0.1%  of  sucrose  the 


12 

reaction  is  obscured  by  the  darkening  of  the  solution;  with  0.01%  sucrose  the  color 
zone  is  that  of  a  very  dark-red  wine;  with  0.001%  sucrose  the  entire  solution  is 
colored.  Impure  water  will  sometimes  impart  a  faint  color  in  the  above  test  in  the 
absence  of  sucrose,  but  this  is  usually  readily  distinguished  from  the  color  produced 
by  sugar. 

Clerget  Tests. — Molasses  Samples. — In  making  these  tests  the  directions  given 
must  be  strictly  complied  with. 

The  direct  polarization  is  to  be  made  as  described  under  Massecuites  and  Molasses. 
The  temperature  of  the  polarization  should  be  noted  and  when  practicable  should 
be  near  20°  C.  The  solutions  should  be  prepared  at  the  temperature  of  the  polariza- 
tion. 

The  invert  polarization  should  be  made  at  the  temperature  of  the  direct,  using  a 
water-jacketed  tube  for  the  purpose.  The  use  of  this  tube  is  also  desirable  in  the 
direct  polarization.  If  the  tube  is  not  fitted  with  desiccator  caps,  except  in  cold  weather, 
it  may  be  necessary  to  make  both  polarizations  at  a  temperature  a  few  degrees  above 
20°  0.  in  order  to  avoid  the  deposition  of  moisture  on  the  cover  glasses. 

It  is  advisable  to  dissolve  2.5  normal  weights  oi  the  molasses  in  500  cc.  in  making 
up  the  solution  for  the  direct  polarization,  io  insure  sufficient  material  for  preparing 
the' invert  solution. 

Remove  the  lead  from  the  solution  used  in  the  direct  polarization,  using  a  strong 
solution  of  potassium  oxalate  as  the  precipitant,  and  adding  a  little  alumina  cream, 
increasing  the  volume  of  the  molasses  solution  10%.  Measure  75  cc.  of  the  deleaded 
solution  into  a  100-cc.  flask,  add  to  it  5  cc.  of  hydrochloric  acid,  containing  38.8 
per  cent  of  the  acid,  and  mix  the  contents  of  the  flask  by  a  circular  motion.  Place 
the  flask  in  a  water-bath  heated  to  70°  C.  and  raise  the  temperature  of  the  sugar 
solution  to  67°-89°  C.  in  two  and  a  half  to  three  minutes,  and  maintain  this  tem- 
perature until  the  total  heating  period  reaches  ten  minutes.  Remove  the  flask  and 
place  it  in  cold  water,  so  as  to  quickly  reduce  its  temperature. 

A  thermometer  should  be  placed  in  the  sugar  solution  during  the  inversion. 
The  inversion  may  be  conducted  at  room-temperature  if  preferred.     After  the 
addition  of  the  acid,  set  the  flask  aside  in  the  laboratory  for  24  hours,  then  prepare 
the  solution  for  analysis. 

After  the  inversion  wash  the  solution  from  the  thermometer  into  the  flabk.  Cool 
the  solution  to  the  temperature  at  which  the  direct  polarization  was  made  and  fill 
the  flask  with  water  to  the  mark.  If  this  solution  is  very  dark,  filter  small  portions 
at  a  time  through  powdered  bone-black,  rejecting  the  first  half  of  the  filtrate,  or 
shake  it  with  one  gram  of  dry  bone-black  in  a  fine  powder;  filter  and  polarize  the 
solution. 

Water  of  the  temperature  at  which  the  direct  polarization  was  made  should  be 
circulated  through  the  jacket  of  the  polariscope  tube  while  making  the  observation. 
Several  readings  should  be  made  and  their  average  and  the  temperature  of  the  solution 
in  the  tube  be  noted.  With  a  sensitive  polariscope  it  is  usually  easy  to  make  these 
observations  accurately  to  0.05°  on  the  cane-sugar  scale.  Great  care  is  essential 
both  in  the  matter  of  the  observation  and  the  temperature,  as  there  is  no  analytical 
work  in  the  sugar  laboratory  more  liable  to  personal  error  than  in  the  invert  polariza- 
tions. The  errors  of  observation  are  multiplied  in  the  calculations. 
The  following  formula  is  to  be  used  in  making  the  calculations: 

Per  cent  sucrose  (Clerget) = —         —^5, 

142.66-4- 


13 

in  which  S  (in  sugar-house  work)  is  the  arithmetic  sum  of  the  direct  and  invert 
readings. 

The  calculations  based    upon  the  strength  of  solutions  given  in  this  article  are 
illustrated  by  the  following  example: 

Direct  reading  (uncorrected  for  dilution)  =  12.1  at  24°  C. 
Invert        "    '  "  "          "        =  -6.55  at  23.7°  C. 

The  direct  reading  corrected  --=  (12.1  +  1.21  )X2  =26.62. 
"    invert       "  "        =  (6.55+0.65)+  0.75X2  =  19.2. 


Per    cent   eucrose    (Clerget)-  -  =  35.02. 

142.66  _±±Z 

Notes  on  Clerget  Tests.  —  In  the  analysis  of  a  sugar  the  half-normal  weight  of  the 
material  should  be  contained  in  75  cc.  of  solution  for  inversion.  Similar  concen- 
tration as  regards  the  sugars  present  should  be  used  in  tests  of  all  materials. 

The  Company's  Run  Reports  require  the  determination  of  the  sucrose  by  the 
Clerget  method  in  the  juice,  sugars,  and  final  molasses.  In  the  case  of  the  juice, 
Clerget  tests  should  be  made  at  frequent  intervals  of  composite  samples  of  the  mixed 
juices  preserved  with  mercuric  chloride,  using  normal  acetate  of  lead  for  clarifying. 
This  procedure  is  advisable  on  account  of  the  precipitation  of  dextrose  and  levulose 
by  the  basic-lead  salt.  These  analyses  are  for  use  in  estimating  the  Clerget  test  of 
the  average  juice  for  the  Run.  If  these  tests  indicate  a  certain  increase  or  decrease 
in  the  sucrose,  as  compared  with  the  direct  polarization,  the  same  percentage  of  change 
is  to  be  applied  to  the  average  polarization  of  the  raw  juice  to  estimate  its  Clerget 
number. 

Ash  Determinations.  —  The  sulphated-ash  method  is  to  be  used  in  all  ash  deter- 
minations. In  this  method  the  material  contained  in  a  shallow  platinum  dish  is 
saturated  with  pure  sulphuric  acid,  then  gently  heated  until  intumescence  ceases- 
The  heat  is  now  to  be  gradually  increased  and  the  carbon  burned.  A  muffle  heated 
to  dull  redness  is  the  best  device  for  ashing  sugar  products.  Care  must  be  exercised 
not  to  fuse  the  ash.  The  sulphuric  acid  must  be  in  sufficient  quantity  to  convert 
the  mineral  constituents  of  the  material  into  sulphates.  To  reduce  the  sulphated 
ash  to  terms  of  the  normal  ash,  deduct  one-tenth  of  its  weight. 

The  following  approximate  quantities  of  the  sugar  products  and  sulphuric  acid 
should  be  used  in  each  test:  2  grams  sugar  and  0.5  cc.  acid;  10  grams  juice  and  1  cc. 
acid;  2  grams  molasses  and  1  cc.  of  acid. 

Methods  of  Drying.  —  With  the  exception  of  the  bagasse,  fiber  (marc),  and  the 
filter  press-cake,  all  dryings  are  to  be  effected  in  a  vacuum  drying  apparatus.  If 
the  laboratory's  facilities  admit,  all  materials  should  be  dried  in  the  vacuum  oven. 

The  drying  of  the  bagasse  and  fiber  has  already  been  described  under  Bagasse. 

Juice,  .  press-cake,  sugar,  and  molasses  should  be  dried  in  very  shallow  dishes. 
The  lead  caps  for  bottles,  3-inch  size,  are  well  adapted  for  this  purpose.  Drying 
should  be  continued  until  the  sample  ceases  to  lose  weight. 

As  a  result  of  many  comparative  tests  by  many  chemists,  the  vacuum  method 
has  been  shown  to  be  the  most  reliable. 

ESTIMATION  OF  THE  PRODUCTS  IN  PROCESS  OF  MANUFACTURE 

Stock-taking.  —  The  laboratory  records  should  include  the  dimensions  and  capac- 
ities of  all  tanks,  pans,  crystallizers,  mixers,  etc.,  in  the  factory.  Each  piece  of 
apparatus  should  bear  a  suitable  mark  for  identification. 


14 

At  the  close  of  a  Run  the  chemist,  accompanied  by  assistants,  should  rapidly 
pass  through  the  factory  and  measure  and  sample  all  material  in  process.  At  the 
same  time  the  head  pan-boiler  should  indicate  with  chalk  the  depth  of  massecuite 
in  each  pan  and  note  its  character.  Beginning  two  or  three  days  before  the  close 
of  a  Run,  the  head  crystallizer  men  should  record  the  "  inches  out"  for  each  crystallizer 
as  soon  as  it  is  filled. 

In  measuring  the  juice  and  syrup  in  the  tanks  it  is  usually  easier  to  measure  the 
depth  of  the  empty  space  from  the  top  of  the  tank,  or,  in  other  words,  the  "  inches 
out,"  rather  than  the  depth  of  the  liquor. 

Samples  should  be  drawn,  representing  each  class  of  material  in  stock.  The 
laboratory  records  will  show  the  analyses  of  the  massecuites,  so  these  need  not  be 
sampled. 

From  these  data  the  quantity  of  materials  of  all  kinds  in  stock,  at  a  given  hourr 
may  readily  be  calculated.  All  stock  data  and  calculations  should  be  entered  in  a 
book  to  facilitate  the  work  of  estimating  and  in  checking  errors.  It  is  preferable 
that  all  the  calculations  be  made  in  the  book  itself. 

It  is  sometimes  more  convenient  to  make  the  stock  estimates  a  little  in  advance 
or  after  the  close  of  the  Run,  in  order  to  take  advantage  of  a  shut-down.  In  the 
one  case  the  cane  ground  from  the  hour  of  stock-taking  to  the  end  of  the  Run  is 
carried  as  "stock,"  and  the  sugar  it  will  produce  is  estimated  on  a  basis  of  the  yield 
for  the  rest  of  the  period.  In  the  other  case  the  estimated  yield  from  the  cane  ground 
from  the  end  of  the  Run  to  the  shut-down  is  to  be  deducted  from  the  total. 

Estimation  of  the  Sugar  in  Process.  —  The  sugar  in  process  in  the  raw  juice  may 
be  estimated  on  a  basis  of  the  "sucrose  retained"  in  a  previous  Run,  or  if  such  data 
are  not  at  hand,  the  "retention"  may  be  estimated  at  88%.  As  the  quantity  of 
raw  juice  in  stock  is  small,  an  over-  or  under-estimate  here  will  introduce  a  very  small 
error.  Likewise  the  yield  from  clarified  juice  may  be  estimated  at  a  somewhat  higher 
rate,  and  that  from  syrup  at  a  still  higher  rate,  as  these  materials  have  already  under- 
gone a  part  of  the  manufacturing  process.  When  first  massecuite  is  made  without 
boiling  in  molasses,  its  sugar  yield  may  be  estimated  upon  the  above  basis. 

When  molasses  is  "boiled-in,"  the  yield  of  sugar  from  the  massecuites  may  be 
estimated  by  means  of  the  following  formula: 

Let  x  =  percentage  yield  of  commercial  sugar  from  the  massecuite; 
B=  degree  Brix  of  the  massecuite; 
P=  polarization  of  the  massecuite;  » 

p=  polarization  of  the  commercial  sugar; 
£=percentage  of  solids  in  the  commercial  sugar; 
M  =  coefficient  of  purity  of  the  final  molasses. 

1COP-BM 

Then  x=  —     -^r-f  —  . 

SM 


This  method  of  calculation  gives  the  yield  of  sugar  with  sufficient  accuracy  for 
the  Run  reports.  The  results  would  be  accurate  if  true  Brix,  polarizations,  and 
purities  could  be  used,  provided  no  solids  are  removed  from  the  molasses  in  the  processes 
of  manufacture  other  than  in  the  sugars. 

The  "above  formula  is  also  used  in  calculating  the  yield  of  sugar  from  the  molasses. 

It  will  be  noted  in  these  methods  that  the  yield  includes  all  of  the  sugar  presumed 
to  be  available,  as  of  one  grade.  If  more  classes  of  sugar  than  one  are  made,  their 


15 

relative  proportions  must  be  ascertained  from  the  experience  of  the  factory  and  the 
calculated  yield  apportioned  accordingly,  figuring  each  class  to  the  average  polari- 
zation for  that  grade  of  sugar. 

Estimation  of  the  Molasses  in  Process. — The  sum  of  the  weights  of  sucrose  in  the 
sugars  made  and  estimated,  in  the  molasses  made,  and  in  the  known  losses,  is  deducted 
from  the  sucrose  received  in  the  juice  to  ascertain  the  sucrose  in  the  molasses  in  process. 
As  there  are  always  unknown  losses  that  can  only  be  measured  by  difference,  the 
sucrose  as  estimated  above  must  be  further  reduced  by  the  factory's  average  of  such 
losses.  The  net  weight  of  sucrose  is  calculated  to  terms  of  final  molasses  on  a  basis 
of  the  estimated  average  purity  of  that  in  process. 

As  the  sucrose  received  in  the  juice  is  calculated  on  the  basis  of  an  analysis  that 
varies  but  little  if  at  all  from  a  Clerget  test  of  this  raw  material,  evidently  Clerget 
tests  and  the  true  purity  of  the  molasses  should  be  used  in  these  calculations. 

For  the  purpose  of  providing  figures  for  comparison  with  the  results  of  previous 
Crops,  the  direct  polarizations  should  be  used  in  calculating  the  "sucrose  account" 
in  the  Run  Reports, 
fc, 

MISCELLANEOUS  CALCULATIONS 

Saturation. — Correct  the  measured  volume  of  the  water  for  expansion  by  the 
customary  tables,  reducing  it  to  the  corresponding  volume  at  4°  C.  The  weight  of 
a  cubic  foot  of  water  at  4°  C.  is  62.427  Ibs. 

62.427  X  cubic  feet  water  at  4°  C.  X 100 

Per  cent  saturation  = .  .  .  ^ — : - . 

Weight  of  cane  in  pounds 

Dilution. — (Brix  of  normal  juice  — Brix  of  diluted  juice) -f-  Brix  of  normal  juice 
XlOO=dilution  %  diluted  juice; 

Diluted  juice  extraction  %  cane  X  dilution  %  diluted  juice-*- 100=  dilution  %  cane. 

Mill  Extraction. — (1)  When  not  saturating:  Mill  extraction  %  cane  =  weight  of 
juice-^-  weight  of  cane X 100. 

(2)  Mill  extraction  when  saturating:  Mill  extraction  %  cane  =  %  mill  extraction 
including  dilution  — dilution  %  cane: 

Weight  of  diluted  juices  weight  of  cane X 100  =mill  extraction  including  dilution  % 
cane; 

Mill  extraction  including  dilution  %  cane  X  dilution  %  diluted  juice  -f- 100  =  dilution 
%  cane. 

There  are  two  methods  of  estimating  the  weight  of  the  juice  from  its  volume 
after  deducting  for  the  entrained  air  and  the  milk  of  lime  added  to  it: 

(1)  Correct  for  expansion  or  contraction  of  the  juice  for  temperatures  above  or 
below  17.5°  C.  by  Gerlach's  table,  showing  the  volumes  of  sugar  solutions  at  different 
temperatures,    or   the   correction   may   be   determined   experimentally.     The   weight 
of  a  cubic  foot  of  water  at  17.5°  C.,  62.348  Ibs.  multiplied  by  the  specific  gravity  of 
the  juice  corresponding  to  its  degree  Brix  at  17.5°  C.,  gives  the  weight  of  a  cubic 
foot  of  the  juice. 

(2)  This  method  is  illustrated  in  the  following  example: 

Degree  Brix  of  the  juice  at  17.5°  C.  =20 .0 
Temperature  of  the  measurement     =27.0 

The  degree  Brix  at  27°  C.,  applying  the  number  in  Gerlach's  table  for  the  correc- 
tion of  readings  on  the  Brix  scale  for  temperature,  is  20.0—0.65  =  19.35,  and  the 


16 

corresponding  specific  gravity  is  1.08039.  The  weight  of  a  cubic  foot  of  juice  at 
17.5°  C.,  62.348  Ibs.X  1.08039 =67.36  Ibs.,  the  weight  at  27°  C. 

It  is  always  preferable  to  actually  weigh  the  juice  when  the  factory  facilities 
permit. 

Bagasse. — When  saturation  is  not  employed:  Per  cent  bagasse  =  100 —  %  mill 
extraction.  When  saturation  is  employed:  Per  cent  bagasse  =  (100  +  %  saturation)  — 
%  dilute  juice. 

These  per  cents  are  in  terms  of  the  weight  of  the  cane. 

Efficiency  of  Saturation. — (1)  Ascertain  the  weight  of  fiber,  juice,  and  water 
entering  and  leaving  the  mills. 

The  juice  remaining  in  the  bagasse  per  cent  juice  entering  the  mills  =  a;  the  water 
remaining  in  the  bagasse  per  cent  water  entering  the  mills  =  6;  1006-f-  a  =  efficiency 
coefficient  of  the  saturation,  i.e.,  the  degree  to  which  the  water  has  mixed  with  the 
juice  in  the  cane.  (After  I.  H.  Morse.) 

(2)  The  following  method  by  E.  E.  Hartmann  is  preferable  to  (1)  when  more 
accurate  results  are  desired: 

Let  A  =  bagasse  from  the  second  mill; 
B  =      "          "      "    third       " 

Diffusion  water  =  the  quantity  of  water,  assuming  complete  diffusion  with 
the  juice  in  the  bagasse,  that  would  bring  the  percentage  of  sucrose  in  A 
to  that  in  B. 

Then 

(Lbs.  sucrose  in  A  X  juice  %  Z?)- (sucrose  %  ffxlbs.  juice  in  A)  . 

Sucrose  %  B  ^diffusion  water(lbs.); 

Coefficient  of  diffusion  (coefficient  of  efficiency)  =  diffusion  water  (Ibs.) -^-saturation 
water  (Ibs.  )X  100. 

When  double  saturation  is  practised,  i.e.,  the  bagasse  from  the  first  mill  is  saturated 
with  the  thin  juice  from  the  last  mill,  the  diffusion  water  is  calculated  from  the  bagasse 
data  of  the  second  and  third  mills,  and  also  from  similar  data  of  the  first  and  second 
mills,  and  these  numbers  are  added  to  ascertain  the  total  diffusion  water. 

This  method  is  applicable  with  any  combination  of  mills. 

Efficiency  of  Mill-work. — A  number  indicating  the  efficiency  of  mill-work  and 
taking  into  account  the  fiber  content  of  the  cane,  is  derived  by  the  following  formula 
of  NoelDeerr.  The  percentages  refer  to  the  analysis  of  the  bagasse:  %  residual  juice 
in  the  bagasse-^  (%  fiber  X  specific  gravity  of  residual  juice)  =  efficiency  number. 

FORMS  SUGGESTED  FOR  LABORATORY  RECORDS 

The  following  forms  are  suggested  for  use  in  systematizing  the  calculations  for 
records  and  reports.  The  width  of  the  columns  must  be  arranged  to  suit  the  work. 
Local  conditions  may  necessitate  a  rearrangement  of  the  ruling: 


17 


p 

P 

o 

1 

£ 

H 

'3 

1 

P 

c3 

P 

CO 

o 

1 

H 

O 
P 

02 
p 
o 

1 

p 

.2 

H 

H 

p 

OJ 

t|O 

od 

J2 

1 

1 

P 

O3 

c 

^ 

o 

T-H 

1 

H 

1 

5 

oj 

GO 

p 

C 
O 

8 

H 

05 

P 

|                   | 

6 

03 

p 

tn 

c 

O 

o 

£-H 

£ 

1 

CO 

1 

•s 

P 

oj 

S 

,2 

PH 

hX) 

3 

-il 

1 

2 
PQ 

&& 

o 

fe 

c 

o 

LI 

3 

(S 

OJ 

j 

.rt 

'3 

CO 

^"3 

p 

t 

o 

oS 

H 

O 

ft 

| 

I 

1 

| 

p 

^ 

o 

Js^ 

/•-N 
* 

% 

H 

IH 

<^            5 

P 

.2 

H     # 
*4      g 
P     ^ 

o 

o 

.^3 

^2 

^           «*H 

c 

S 

0      ° 

O 

XTRACTI 

hand  page 

fS 

3 

- 

W     ^ 

P 

6 

bfi 

.  »s  Q} 

^ 

a 

N_X 

fl.S 

.2^ 

^ 

£ 

IP 

p 

p 

IH 

o 

<B 

fe 

dH 

3 

CQ 

^-K 

P 

r~i 

O 

o 

H 

1 

H 

oj 

PQ 

JH 

03 

O 

'—, 

S 

18 


02 


? 


& 


:  a 


0   0 

HH 


M    ,0 
02  «+-, 

3S 

|2 

•§ 

Q  g 


o  c 


02 


II 

02 


§ 


PQ 


19 


49 
03 

H 

0! 

43 

a 

i 

o 

CQ     CO 

i 

H 

F 

02 

! 

li 

5 

<D 
CQ 

$ 

02 

Q 

*| 

OS 

Q 

r  . 

02 

S-, 

-u 

-j 

S) 

g 

« 

i—  i 

of 

CB     03 

S  S 

1 

1 

£ 

? 

M 

02 

1 

tyl 

0) 

H 

o 

9  -£ 

•H-i 

5  'S 

OS 

Q 

i 

O- 

O  £ 

^ 

i! 

li- 

ZT1 ^ 

02   «*-. 

I 

1 

O   §o 

^     03 

c3 

do 

S    1 

1 

oT 

03    02 

^ 

i 

"C5 
1 

fcJD 

la 

li 

i 

II 

02 

£ 

I 

E 

^ 

O  Jj 

s.i 

s 

Q 

s 

o 

"i 

fe 

H 

jjj 

CS    CO 

1 

S 

? 

O    f- 

1 

•  c 

OQ  ^O 

oo 

| 

!    «3 

^§ 

ed 

"2 

•       Q 

Q 

M 

B5 

•  '> 

-6 

ii 

6 

f 

q 

§ 

1 

tJD 
1 

"C    <U 

1 
1 

0s*  O 

1 

20 


The  above  forms  provide  for  the  calculations  of  weighted  averages  and  for  bringing 
all  averages  to  date  daily,  as  is  desired  in  certain  of  the  Company's  factories.  For 
example,  in  the  calculation  of  the  analysis  of  the  diluted  and  the  normal  juices: 
Brix- tons -r-  diluted  juice,  tons  XI 00  =  degree  Brix  of  diluted  juice  and  Brix-tons-^ 
normal  juice,  tons  XI 00=  degree  Brix  of  the  normal  juice.  These  figures  are  to  date 
or  for  the  Run,  according  to  the  data  used.  The  same  weights  for  Brix,  sucrose,  and 
glucose  are  used  for  both  the  diluted  and  normal  juice. 

In  the  case  of  the  sugars,  the  number  of  bags  multiplied  by  their  tests  gives  the 
"sucrose-bags,"  and  the  total  sucrose-bags-f-  total  number  of  bags  =  average  test. 


